This invention relates generally to a system for supporting the inner container of a cryostat, more particularly a system for maintaining the spacing and supporting a cryogen container from surrounding warmer walls with reduced heat loss through the support system.
Cryogenic materials, such as liquefied and solid gases, are frequently stored in cryostats or cryogenic containers for use in orbiting spacecraft. Such cryostats are designed to minimize the transfer of heat from the outer vacuum jacket and environment surrounding the cryostat to the cryogenic material. Notwithstanding cryostat design techniques, cryogenic material is lost in the heat transfer accompanying the imperfections of the insulation, the plumbing, the electrical wiring, and the supporting structure of the cryostat. The heat leak associated with the supporting structure for the inner container of a cryostat can be as much as 60 percent of the total heat transfer loss and, thus, constitute a significant contribution to the loss of cryogenic material from the system and make a significant reduction in the useful life of cryogenic systems of spacecraft.
In the past, orbital cryogenic systems have used fiberglass-epoxy tension band supports within the cryostat for the cryogen container. In such systems, however, the epoxy-fiberglass-tension bands connected directly portions of the cryogen container with the surrounding warmer-walled vacuum jacket. Such systems have provided a significant heat leak between the spacecraft environment and the contained cryogenic material of the system. The container supports must, of course, have sufficient strength to support the container and its contents against the significant loads imposed on the supporting structure by the acceleration accompanying the launch of the spacecraft. During such a launch, the larger forces imposed by the acceleration of the launching rockets must be borne entirely by the cryogen container supports at a time when the container has its greatest mass. Since the prior art tension band supports were designed with sufficient size to carry the forces imposed by the container and its contents during launch, they have provided a significant path for heat transfer to the cryogenic material in the container.